Add simics breakpoint for exceptions

Created a new magic instruction handler that can be enabled via
environment variable to stop the simulation for Hostboot
exceptions.  This is useful when we want to get a backtrace at
the failing spot without recompiling code or having to manually
insert breakpoints in simics directly.

Enable the function by setting HB_BREAK_ON_ERROR
The trigger call is MAGIC_BREAK_ON_ERROR

Change-Id: I17e008281d010e3f8c5e5817e5f30fd0ccb624d0
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/24600
Tested-by: Jenkins Server
Tested-by: FSP CI Jenkins
Reviewed-by: William G. Hoffa <wghoffa@us.ibm.com>
Reviewed-by: Marshall J. Wilks <mjwilks@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/include/arch/ppc.H b/src/include/arch/ppc.H
index 455728500..7e8b768c2 100644
--- a/src/include/arch/ppc.H
+++ b/src/include/arch/ppc.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2011,2015                        */
+/* Contributors Listed Below - COPYRIGHT 2011,2016                        */
 /* [+] Google Inc.                                                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
@@ -466,6 +466,8 @@ enum
     MAGIC_WAKE_MASTER_THREAD  =  7015, // Wake master thread
     MAGIC_WAKE_OTHER_THREADS  =  7016, // Wake other threads on initial CORE
     MAGIC_WAKE_FUSED_THREADS  =  7017, // Wake up fused core threads
+    MAGIC_BREAK_ON_ERROR      =  7018, // Breakpoint in error cases if
+                                       //  env var HB_BREAK_ON_ERROR
 
     MAGIC_CONTINUOUS_TRACE    =  7055, // extract mixed trace buffer
 };